Jetty version
9.4.25.v20191220
Java version
OpenJDK build 1.8.0_232-09
OS type/version
Linux 4.15.0-74-generic #83~16.04.1-Ubuntu
Description
If the "X-Forwarded-Port" header is present but empty, a NumberFormatException is thrown:

java.lang.NumberFormatException: For input string: ""

This is likely not a correct state for the headers, but it would be nice to at least have a more descriptive error message.

Unfortunately there is no way for me to influence the header value that I receive, so any workarounds for this would be appreciated as well.